Breeding tiny flying syringes

(photo found here)

Some Japanese researchers have genetically engineered mosquitoes so they'll deliver vaccines when they bite. As this article in Science magazine says, it's probably "unworkable but very cool."

Mosquitoes inject a bit of their saliva with every bite (which keeps the blood from clotting), so these researchers added a compound to the saliva which will create an immune response in the host. They've even created mosquitoes that carry a "candidate malaria vaccine." Then, every bite is like a tiny vaccination. And presumably, the mosquitoes would breed true.

Cool, indeed! So why is it unworkable?

There's a huge variation in the number of mosquito bites one person received compared with the next, so people exposed to the transgenic mosquitoes would get vastly different doses of the vaccine; it would be a bit like giving some people one measles jab and others 500 of them. No regulatory agency would sign off on that,... Releasing the mosquitoes would also mean vaccinating people without their informed consent, an ethical no-no. [Shigeto] Yoshida concedes that the mosquito would be "unacceptable" as a human vaccine-delivery mechanism.

Too bad, huh? Admittedly, mosquitoes would still be just as annoying, but maybe not so dangerous.